Acute coronary syndromes
Resident Survival Guide |
Acute Coronary Syndrome Chapters |
AHA/ACC Guidelines for Acute Coronary Syndrome |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Yamuna Kondapally, M.B.B.S[2]; Tarek Nafee, M.D. [3]; Sabawoon Mirwais, M.B.B.S, M.D.[4]
Synonyms and keywords: ACS
Overview
Acute coronary syndrome (ACS) refers to any group of symptoms attributed to obstruction of the coronary arteries. The most common symptom prompting diagnosis of ACS is chest pain, often radiating to the left arm or angle of the jaw, pressure-like in character, and associated with nausea and sweating. Acute coronary syndrome usually occurs as a result of one of three problems: ST-elevation myocardial infarction (30%), non ST-elevation myocardial infarction (25%), or unstable angina (38%). These types are named according to the appearance of the electrocardiogram. There can be some variation as to which forms of myocardial infarction (MI) are classified under acute coronary syndrome. ACS should be distinguished from stable angina, which is chest pain that develops during exertion and resolves at rest. New-onset angina however should be considered as a part of acute coronary syndrome, since it suggests a new problem in a coronary artery. Though ACS is usually associated with coronary thrombosis, it can also be associated with cocaine use. Cardiac chest pain can also be precipitated by anemia, bradycardias or tachycardias.
Classification
- Traditionally, ACS has been classified into:
- According to this classification, unstable angina was defined as clinical and electrocardiographic (ECG) evidence of myocardial ischemia in the absence of an elevated troponin level.
- However, the widespread use of the high-sensitivity troponin assays made UA and NSTEMI indistinguishable since it was shown that almost all patients previously named UA actually have increased high-sensitivity troponin levels.
- In other words, it is very unlikely that patients with clinical and ECG evidence of myocardial ischemia have normal high-sensitivity troponin levels.
- Consequently, in recent guidelines, acute coronary syndrome is classified into two broad categories:
Causes
- ACS is characterized by a sudden imbalance between myocardial oxygen consumption and demand, which is usually the result of coronary artery obstruction.
- The most common causes of coronary artery obstruction are:
- Atherosclerotic plaque rupture and subsequent coronary thrombus
- Other conditions may also cause an imbalance, including:
- Excessive myocardial oxygen demand (in the setting of a stable flow-limiting lesion)
- Coronary artery spasm causing vasospastic (Prinzmetal) angina
- Coronary embolism
- Coronary arteritis
- Noncoronary causes of myocardial oxygen supply-demand mismatch :
- Hypotension
- Severe anemia
- Hypertension
- Tachycardia
- Hypertrophic cardiomyopathy
- Severe aortic stenosis
- Nonischemic myocardial injury:
- Multifactorial causes:
- [[Stress (Takotsubo) cardiomyopathy]]
- Pulmonary embolism
- Severe heart failure (HF)
- Sepsis
For a complete list of causes for UA click here, for NSTEMI click here, and for STEMI click here.
Differentiating Acute coronary syndromes from other Diseases
- Diagnosis of ACS is initiated by a clinical suspicion based on a thorough history of the patient's symptoms.
- Subsequently, confirmatory tests should be ordered to confirm the diagnosis, identify the specific cause of ACS, or to rule out other possible differentials.
- In some circumstances, utilizing a clinical prediction tool may be beneficial in guiding the clinician's diagnosis.
- View the page on diagnosis using the clinical prediction rule for ACS for more detail.
- Acute Coronary Syndrome (ACS) may be differentiated from other diseases as follows:
Organ System | Diseases | Presentation | Diagnostic Tests | Past Medical History | Other Findings | |||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chest Pain | GI Symptoms | Pulmonary | Neck | |||||||||||||||||||||
On Palpation | On inspiration | Radiating to Extremeties | Radiating to Back | With Movement | Nausea or Vomitting | Epigastric Pain | Odynophagia or Dysphagia | Shortness of Breath | Jugular
Distention |
Cardiac Biomarkers | CBC Findings | ESR | D-Dimer | EKG
Findings |
CXR Findings | DM | Hyperlipidemia | Obesity | Trauma | Inxn* | Htn | |||
Cardiovascular | Acute Coronary Syndrome | + | + | + | + | + | + | + | + | + | + | + | •Palpitations | |||||||||||
Aortic Dissection | + | + | + | - | + | + | - | + | •Pain maximal upon onset •Pain difficult to treat with opiates
•Weak pulse in one arm compared to other •Symptoms similar to stroke | |||||||||||||||
Brugada Syndrome | No chest pain | + | •Syncope
•ST-segment elevation •F/H of sudden cardiac death | |||||||||||||||||||||
Takotsubo carditis | Sudden onset of chest pain mimicking myocardial infarction | + | + | + | + | + | - | •Extreme emotional or physical stress•syncope
•Women>men •ST segment elevation •Left ventricular apical ballooning on echo •Normal coronary arteries | ||||||||||||||||
Pericarditis | + | + | + | •Relieving factor: Sitting up and leaning forward
•Aggravating factor: Lying down and breathing deep |
+ | + | + | + | + | + | + | •Other causes:Malignancy, autoimmune disorders, chest trauma | ||||||||||||
Organ System | Diseases | Presentation | Diagnostic Tests | Past Medical History | Other Findings | |||||||||||||||||||
Chest Pain | GI Symptoms | Pulmonary | Neck | |||||||||||||||||||||
On Palpation | On inspiration | Radiating to Extremeties | Radiating to Back | With Movement | Nausea or Vomitting | Epigastric Pain | Odynophagia or Dysphagia | Shortness of Breath | Jugular
Distention |
Cardiac Biomarkers | CBC Findings | ESR | D-Dimer | EKG
Findings |
CXR Findings | DM | Hyperlipidemia | Obesity | Trauma | Inxn* | Htn | |||
Pulmonary | Pleuritis (pleurisy) |
+ | + | + | + | •Aggravating factor: Deep breathing | + | + | + | + | + | + | •Other causesPulmonary embolism, malignancy, autoimmune diseases | |||||||||||
Pulmonary Embolism | + | •Aggravating factors: Deep breathing, coughing, eating, bending and stooping | + | + | + | •Other causes: Immobility, pregnancy, oral contraceptive pills | ||||||||||||||||||
Pneumonia | + | + | + | + | + | + | •Complications: Sepsis, ARDS, Lung abscess | |||||||||||||||||
Gastrointestinal | GERD | + | + | + | •Other symptoms: Hoarseness, Dry cough at night, Sensation of lump in throat etc | |||||||||||||||||||
Esophageal Spasms | + | + | + | + | + | + | + | • Risk factors: Anxiety or depression and drinking wine, very hot or cold foods | ||||||||||||||||
Esophagitis | + | + | + | + | + | + | + | • Causes: Hiatal hernia, infection, medications, radiation therapy | ||||||||||||||||
Gastritis | + | + | + | + | + | + | + | • Causes: H.pylori infection, bile reflux, alcohol use, alcohol use | ||||||||||||||||
Organ System | Diseases | Presentation | Diagnostic Tests | Past Medical History | Other Findings | |||||||||||||||||||
Chest Pain | GI Symptoms | Pulmonary | Neck | |||||||||||||||||||||
On Palpation | On inspiration | Radiating to Extremeties | Radiating to Back | With Movement | Nausea or Vomitting | Epigastric Pain | Odynophagia or Dysphagia | Shortness of Breath | Jugular
Distention |
Cardiac Biomarkers | CBC Findings | ESR | D-Dimer | EKG
Findings |
CXR Findings | DM | Hyperlipidemia | Obesity | Trauma | Inxn* | Htn | |||
Musculoskeletal | Muscle sprain/Spasm | + | + | + | + | • Causes: Over use, dehydration, electrolyte abnormalities | ||||||||||||||||||
Costochondritis | + | + | + | + | + | + | + | + | + | + | + | • Risk factors: Rheumatoid arthritis, ankylosing spondylitis, Reiter's syndrome | ||||||||||||
Rib fracture/Trauma | + | + | + | + | + | + | + | + | + | + | • Complications: Pneumothorax, hemothorax, surgical emphysema | |||||||||||||
Psychiatry | Anxiety (Panic Attack) | Chest tightness | + | + | • Other symptoms: Palpitations, trembling, sweating, choking, light headed, hot or cold flashes. |
The following table summarizes the significant history, and diagnostic test findings that will help differentiate the acute coronary syndromes from one another, as well as from other coronary artery diseases:
Acute Coronary Syndromes | History and Symptoms | Pathology | Diagnostic tests | Treatment | Complications | Prognosis | |||||
---|---|---|---|---|---|---|---|---|---|---|---|
Chest pain | Duration of Chest pain | Coronary Artery | Plaque | Cardiac Biomarkers (e.g.CK-MB, Troponins) |
EKG Findings | Medical Therapy | Reperfusion (e.g. PCI, CABG, or Medical) | ||||
At Rest | Exertion | ||||||||||
Unstable Angina | + | + | <30 minutes | Partial occlusion | Erosion
or (39%) |
Normal | •Normal EKG findings (some cases)
|
+ | •Arrhythmias
•MI •Sudden death |
•1 year mortality rate is 1.7% | |
NSTEMI | + | + | >30 minutes | Partial or complete occlusion | Rupture
(56%) or Erosion |
Elevated | •No EKG findings (some cases)
|
+ | + | •Arrhythmias
•Sudden death |
•1 year mortality rate is 24.4%
•30 day mortality rate is about 2% |
STEMI | + | + | >30 minutes | Complete occlusion | Rupture
(50%-75%) or Erosion |
Elevated | •ST elevation in at least 2
contiguous leads in V2-V3
two precordial leads V1-V4
leads plus ST elevation in lead aVR (suggestive of occlusion of the left main or proximal LAD artery)
|
+ | + | •Reinfarction
interventricular septum and LV free wall •Sudden death |
•30 day mortality rate is
1.1% in <45 yrs and 20.4% in >75 yrs patients |
Other Coronary Artery Diseases | |||||||||||
Chronic stable angina | - | + | ≤ 5 minutes | Severely narrowed | Stable plaque | Normal | •Normal EKG in 50% of cases
•Down sloping, up sloping or horizontal ST segment depression •T wave inversion |
+ | •Heart failure | •Estimated annual mortality rate is 0.9%-1.4%
•Annual incidence of non-fatal MI between 0.5%-2.6% •1 year mortality rate is 1.3% | |
Prinzmetal's angina | •Occur at rest
(Mid night to early morning) •Not associated with exertion |
5-30 minutes | Coronary artery vasospasm | - | Normal | •Transient ST segment elevation | + | •Arrhythmias
•MI |
•5 year survival is excellent (90%-95%) |
Differential Diagnoses of Acute Coronary Syndromes in the Setting of Chest Pain
Cardiac | Pulmonary | Vascular | Gastrointestinal | Orthopedic | Other |
---|---|---|---|---|---|
Myopericarditis
Cardiomyopathiesa |
Pulmonary embolism | Aortic dissection | Esophagitis, reflex or spasm | Musculoskeletal disorders | Anxiety disorders |
Tachyarrhythmias | (Tension)-Pneumothorax | Symptomatic aortic aneurysm | Peptic ulcer, gastritis | Chest trauma | Herpes zoster |
Acute heart failure | Bronchitis, pneumonia | Stroke | Pancreatitis | Muscle injury/inflammation | Anemia |
Hypertensive emergencies | Pleuritis | Cholecystitis | Costochondritis | ||
Aortic valve stenosis | Cervical spine pathologies | ||||
Tako-Tsubo cardiomyopathy | |||||
Coronary spasm | |||||
Cardiac trauma | |||||
Bold = Common and/or important differential diagnoses
aDilated, hypertrophic and restrictive cardiomyopathies may cause angina or chest discomfort |
Diagnosis
Diagnostic study of choice Diagnosis of acute coronary syndrome needs a combination of:
- careful history
- physical examination
- Electrocardiography (ECG)
- serum markers of myocardial injury
- According to the 2014 ACC/AHA guidelines for managing Non-ST-elevation ACS, clinical assessment and initial evaluation of patients with suspected ACS should include risk stratification based on the likelihood of ACS as well as adverse clinical outcomes. These assessments would help for the decision on the need for hospitalization and guide in choosing appropriate treatment strategies.
- In all patients with suspected ACS these two questions should be answered:
- 1) What is the likelihood that this patient is having ACS?
- The likelihood that symptoms and signs represent an ACS can be assessed according to the table below.
- 1) What is the likelihood that this patient is having ACS?
"The likelihood that Signs and symptoms reflect an underlying ACS"
Feature | High
(Any of the Following) |
Intermediate
(Absence of High-Likelihood Features and Presence of Any of the Following) |
Low
(Absence of High- or Intermediate-Likelihood Features but May Have the Following) |
---|---|---|---|
History |
|
|
|
Physical examination |
|
|
|
ECG |
or
|
or
|
|
Cardiac markers |
|
|
|
- 2) What is the likelihood of adverse clinical outcome(s) in this patient?
- Several risk assessment scores and clinical prediction algorithms have been used to identify patients who are at high risk of developing adverse outcomes.
- These risk scores and algorithms use an integration of clinical history, physical examination findings, ECG, and cardiac troponins.
- The most common risk assessment tools include:
- TIMI (Thrombolysis In Myocardial Infarction) risk score
- PURSUIT (Platelet Glycoprotein IIb/IIIa in Unstable Angina: Receptor Suppression Using Integrilin Therapy) risk score
- GRACE (Global Registry of Acute Coronary Events) risk score
- NCDR-ACTION (National Cardiovascular Data Registry-Acute Coronary Treatment and Intervention Outcomes Network) registry (https://www.ncdr.com/webncdr/action/).
- 2) What is the likelihood of adverse clinical outcome(s) in this patient?
- The following risk scores have been designed to specifically assess patients presenting to the ED with chest pain:
- Sanchis score
- Vancouver rule
- Heart (History, ECG, Age, Risk Factors, and Troponin) score
- HEARTS3 score
- Hess prediction rule
- The following risk scores have been designed to specifically assess patients presenting to the ED with chest pain:
| History and Symptoms The symptoms of acute coronary syndrome include:
- Chest discomfort described as:
- pain
- pressure
- tightness
- burning.
- In contrast to the pain described in stable angina as deep, poorly localized retrosternal chest discomfort that is reproducible with activity or emotional stress and relieved promptly (within less than 5 minutes) by rest and/or short-acting nitroglycerin, ACS patients tend to experience the episodes that are more severe and prolonged, may occur at rest, or may be precipitated by less exertion than the patient's previous experiences.
- Pain frequently radiates to the left arm, left shoulder, back, jaw, neck, or epigastric region
- Some patients may not have chest pain and present with other symptoms, known as "anginal equivalents", including:
- Dyspnea (most common)
- Nausea and vomiting
- Diaphoresis
- Unexplained fatigue
- Syncope may be a rare presentation of ACS.
The following features are usually in favor of the non-ischemic nature of pain:
- Pleuritic pain: sharp or stabbing pain increased in intensity by respiration or cough
- Pain reproduced with movement or palpation
- Pain which can be localized by the tip of 1 finger
- Brief episodes of pain (lasting a few seconds)
- Pain with maximal intensity at onset
- Primary or the only location of pain in the middle or lower abdomen
- Pain radiating to lower extremities| Physical Examination | Laboratory Findings | Electrocardiogram | X-Ray Findings | Echocardiography and Ultrasound | CT-Scan Findings | MRI Findings | Other Imaging Findings | Other Diagnostic Studies
- To view the treatment of urinary tract infection click here.
- To view the detailed treatment of Unstable angina/ NSTEMI click here.
- To view the detailed treatment of STEMI [STEMI resident survival guide|click here]].